Plug handling apparatus for seamless tube mill



G. C. KELLY Get, 11, 1966 PLUG HANDLING APPARATUS FOR SEAMLESS :TUBEMILL Filed Sept. 9, 1965 8 Sheets-Sheet l INVENTOR. GEORGE C. KELLYATTORNEY G. C. KELLY PLUG HANDLING APPARATUS FOR SEAMLESS TUBE MILLFiled Sept. 9, 1963 8 Sheets-Sheet 2 Ikr Linn;

ON i

INVENTOR. GEORGE C. KELLY W1? M 44 ATTORNEY G. C. KELLY PLUG HANDLINGAPPARATUS FOR SEAMLESS TUBE MILL Filed Sept. 9, 1963 8 Sheets-Sheet 3iiiiv INVENTOR. GEORGE C. KELLY BY W ATTORNEY- 1966 e. c. KELLY 3,277,6

PLUG HANDLING APPARATUS FOR SEAMLESS TUBE MILL Filed p 1963 8Sheets-Sheet 5 INVENTOR GEORGE C. KELLY BY W6 ATTORNEY 1966 G. c. KELLY3,277

PLUG HANDLING APPARATUS FOR SEAMLESS TUBE MILL Filed Sept. 9, 1963 8Sheets-Sheet 6 INVENTOR. GEORGE C. KELLY BYM/KM ATTORNEY Oct. 11, 1966a. c. KELLY 3,277,67

PLUG HANDLING APPARATUS FOR SEAMLESS TUBE MILL Filed Sept. 9, 1963 8Sheets-Sheet INVENTOR. GEORGE C. KELLY ATTORNEY G. C. KELLY Oct. 11,1966 PLUG HANDLING APPARATUS FOR smmmsss TUBE MILL filed Sept. 9, 1963 8Sheets-Sheet 8 68 34 :24

INVENTOR.

- GEORGE O. KELLY W6 24% ATTORNEY U ited States Patent 3,277,687 PLUGHANDLING APPARATUS FOR SEAMLESS TUBE MILL George C. Kelly, Minneapolis,Minn., assignor to General Mills, Inc., a corporation of Delaware FiledSept. 9, 1963, Ser. No. 307,618 13 Claims. (Cl. 72-209) This inventionrelates generally to apparatus used in the operation of a seamless tubemill. More particularly, this invention relates to a novel apparatus tobe'used in that portion of the seamless mill operation where a piercedbillet or shell is fed through a plug rolling mill (which is part of theoverall seamless tube mill) so as to be moved over a forming plugmounted on the front end of a mandrel, which novel apparatus functionsto automatically replace the plug on the mandrel after each formingoperation and to cool the several plugs used in sequence on the mandrel.

Seamless steel tubing has for many years been used commercially in greatquantities (for example, the oil drilling industry uses it extensively)and there has been continuous eifort to improve the operation ofseamless tube mills with respect to general cost reduction, efficiency,safety, etc. Yet the present operation of a plug rolling mill requires athree man team: an operator for the hydraulic ram which pushes thepierced billet or shell into the work rolls; a plugger who with a largeset of tongs suspended from an overhead cable removes one plug from themandrel, drops this hot plug into a water bath and replaces it with acool plug; and a roller who signals the ram operator and with a hook orset of tongs rotates the shell ninety degrees between a first and asecond forming operations. (Sometimes the roller also does the work ofthe ram operator, thus making it a two man team.) The heat from theshells (which may be at a temperature of perhaps 1,900 degrees F.), thephysical exertion required in handling these heavy plugs, and otherfactors make the working conditions for the plugger sufficiently severeso that a group of three pluggers are rotated (twenty minutes on andforty minutes off on each eight hour shift). With the plant operating ona twentyfour hour schedule, the labor expensealone in the operation of aplug rolling mill is considerable.

Also in such an operation, where the feeding in and feeding out of alarge hot billet or shell must be coordinated with the movements of theplugger, there is, in attempting to keep a good steady pace ofproduction, a danger in the ram operator or roller initiating one ofthese mechanical steps too closely after one of the operating movementsmanually performed by the plugger. For example, if the plugger shouldtake ahold of a plug mounted on the mandrel, begin to remove the plug,and then hesitate to take a firmer grip with his tongs, there is apossibility that the roller will not be alert to this delay, and willcause the outfeed of the shell when the plugger is not clear of theoutfeed path of the shell. To reduce the probability of suchoccurrences, the operating sequence must necessarily be performed with acertain degree of caution. Thus primarily for safety and also forconsiderations of better production, it wouldbe a desirable improvementif this plug replacing operation could be performed without so exposingthe workers to such dangers.

The plugs themselves are a source of some expense in the operation. Forlarger diameter pipe, the forming plug may Weigh as much as two hundredpounds,-and it must be maintained in a predetermined shape withinreasonably close tolerances. With the pluggerl handling these plugsunder the severe conditions as described above, occasionally a plug isdropped on the floor or tumbled into the water bath improperly, thusdamaging the plug or shortening its useful life.

Because of the difliculties and problems of the plug replacing operationof a plug rolling mill, various approaches have. been taken to alleviatethe same, either replacing the plug mechanically, replacing the plug andmandrel as a unit mechanically or devising other means which in somemanner eliminate this manual handling of the plugs. But for variousreasons, to the best knowledge of this applicant, none of these have metwith any appreciable degree of commercial acceptance.

Accordingly, it is an object of the present invention to provide for aplug rolling mill a practical apparatus to accomplish mechanically theproper replacement and cooling of the forming plugs of a plug rollingmill.

It is a further object to provide such an apparatus which can readily beinstalled in the general type of seamless tube rolling mills commonlyfound in various commercial operations so as to require littleadaptation of such existing mill installations, other than adding theapparatus of the present invention.

More specifically, my invention purports to accomplish the twopreviously mentioned objects by providing an improved apparatuscomprising a plug manipulator, plug cooler, and mandrel positioner whichcooperate in the following manner: the plug manipulator removing a hotplug from the mandrel and inserting it into a magazine of the plugcooler, and then receiving a cooled plug from the plug cooler andplacing it on the mandrel; the plug cooler functioning to receive eachof the hot plugs, move them through a water bath and deliver each of thethus cooled plugs in sequence to the manipulator; and the mandrelpositioner, as its name implies, properly locating the mandrel so that acooled plug can be inserted thereon.

These and other objects and features of the invention will be morereadily understood and appreciated from the following detaileddescription of the preferred embodiment thereof selected for purposes ofillustration and shown inthe accompanying drawings, in which:

FIGURES 1 through 8 are semi-schematic drawings taken generally in sideelevation with portions thereof shown in section, these figuresillustrating the sequence of operation in a conventional plug rollingmill;

FIGURES 1A, 6A, and 7A are sectional views taken on, respectively, lines1A1A, 6A-6A, and 7A7A of, respectively, FIGURES 1, 6 and 7, andillustrating the configuration and disposition of a pierced billet orshell during those portions of the operation illustrated in FIG- URES 1,6 and 7;

FIGURE 2A is a transverse sectional view taken on line 2A-2A of FIGURE 2to illustrate the configuration of the work rolls of a conventional plugrolling mill;

FIGURE 9 is a top plan view, illustrating in full lines the boom in itsfull left loading and unloading position, and in broken lines its fullright plug replacing position and its intermediate working position. Forclarity, a positioning jack shown in perspective in FIGURE 14 isomitted; also the bridge is shown partly in section as indicated at line99 of FIGURE 14.

FIGURE 10 is a view taken on line 10-10 of FIGURE 9- FIGURE 11 is a sideelevational view of the apparatus of the present invention, with thebell housing of the seamless tube mill shown in section, and the workrolls and the mandrel being shown in broken lines;

FIGURE 12 is a rear elevational view of the apparatus of the presentinvention;

FIGURE 13 is a perspective view of the plug cooler portion of theapparatus of the present invention;

FIGURE 14 is a perspective view of the manipulator of the presentinvention;

,FIGURE 15 is a fragmentary side elevational view of the manipulatorboom of the present invention, with portions thereof shown in section;

FIGURE 16 is a front elevational view taken at line 16- 16 of FIGURE 15,and

FIGURE 17 is a longitudinal sectional view taken on line 17-17 o-fFIGURE 16.

It is believed a clearer understanding of the present invention will beattained by first indicating the apparatus and operating procedure nowcommonly used in conventional plug rolling mills; then describing thestructure of the plug manipulator. and mandrel positioner of myinvention, and the manner in which these components cooperate with theconventional existing apparatus of a plug rolling mill; and finallydescribing the structure and operation of the plug cooler of myinvention and pointing out the manner in which this plug coolercooperates with the plug manipulator and the existing plug rolling millapparatus.

Before a steel billet is delivered to the plug rolling'mill portion ofthe overall seamless tube milling operation,

the billet has been heated to about 1,900 degrees F., and then passed acouple of times through a piercing mill.

, In the piercing operation, the billet is fed by rollers onto apiercing mandrel to form a hole in the billet to give it the overallconfiguration of a cylindrical shell. the piercing operation, the billetis reheated and then rolled down a ramp into a trough formed in astationary bed, at which trough location the billet begins to beprocessed through the plug rolling mill, for which the apparatus of thepresent invention is provided.

The sequence of operation of a typical prior art plug rolling mill (notconsidering for the moment the apparatus of the present invention) isillustrated schematically in FIGURES 1 through 8. Numeral 10 designatesthe aforementioned bed having the receiving trough 12 in which thepierced billet or shell 14 is deposited after having been reheatedsubsequent to the piercing operation. Aligned with, and located behind,the trough 12 is a pneumatic cylinder 16 having a ram 18, which (asillustrated in FIGURE 1 and 2) functions to push the shell 14 through abell housing 20, which guides the shell 14 onto aforming plug 22 locatedbetween continuously rotating upper and lower work rolls 24 and 26,respectively, and mounted on the free rear end of a mandrel 28.

These work rolls 24and 26 are large, heavy, generally cylindrical metalpieces, formed with matching rounded circumferential grooves 30 and 32(as illustrated in FIG- URE 2A) in which the rolls 24 and 26 grip theshell 14. These rolls 24 and 26 function to shape the shell 14 over theplug 22 by moving it over the plug 22 and mandrel 28. After the workrolls 24 and 26 have so gripped the shell 14, the ram 18 retracts (asindicated in FIGURE 3). Several guideways 34 are provided along thelength of the mandrel 28 so. as to properly support the shell 14circumjacent the mandrel 28. When the shell 14 has reached its furthestin or forward position of travel (as shown in FIGURE 4), the formingplug 22 is manually removed from the mandrel 28 in the aforedescrihedmanner (the plugger gripping with a pair. of tongs a protruding nosepiece 36 of the plug 22 and pulling the plug 22 off the mandrel 28 Whenthe plugger has so removed the plug 22, the man who works as the rollerpushes a control button which opens the Work rolls 24 and 26 and causesa pair of continuously rotating stripper rolls 38 and 40, respectively,located forward of, and constructed similarly. to, the work rolls 24 and26, to grip the shell 14 (as illustrated in FIGURE and move the shell 14(as illustrated in FIGURE 6) out or rearwardly and into the trough 12formed in the bed 10. The speed with which the stripper rolls 38 and 40eject the shell 14 is sufiicient to carry the shell 14 to its furthestrearward or out positioninthe trough 12.

At this time, the plugger, having deposited the hot After plug 22 inaWater bath, now takes with the tongs a cool plug 22 and places the sameonto the end of the mandrel 28. At the same time the roller takes holdof the ejected shell 14 with a hook or a pair of tongs and rotates theshell 14 ninety degrees (from the position shown at 6A to that shown at7A), preparatory for a second plug rolling operation. This is done toeliminate the longitudinal bulges or concentrations of material 42formed on each side of the shell 14 on its first pass through the plugrolling mill, this being illustrated in the sectional views of the shell14 in FIGURES 6A and 7A. When the cool plug is positioned on the mandrel32 (as shown in FIGURE 7) and the plugger is clear of the path of thepath of the shell 14, the roller signals the ram operator, and the shell14 is again fed into the work rolls 24 and 26 (which are now closed) bymeans of the ram 18 (as illustrated in FIGURE 8). After this second plugrolling operation, the ejected shell 14 is moved from the trough 12 toanother station where the shell 14 is put through a subsequent reelingoperation.

To describe now the apparatus of the present invention, numeral 50designates generally the plug manipulator of this invention, whichmanipulator comprises a stationary bridge 52 disposed above andtransversely of the feed path of the shell 14 in the plug rolling mill,and a carriage 54 mounted for back and forth movement along the lengthof the bridge 52 (i.e. transversely of the feed path of the shell 14).The bridge 52 is rigidly mounted from the floor or other stationarysurrounding structure and is constructed as a horizontally disposedframe having a generally rectangular configuration. The two longitudinalframe components are a pair of I beams 56, each of which provides asuitable track for heavy duty wheels 58 mounted on the carriage 54. TheI beams 56 are joined at each end by cross pieces 60 of the bridgeframe, and are braced at intervals along the length thereof by crossbraces 62 welded or otherwise secured to the top side of the I beams 56.

Located between the I beams '56 of the bridge 52 is agenerallyrectangular upper carriage frame 64 on each side of which aremounted the aforementioned carriage wheels 58 which track to the I beams56. Rigidly fixed to and depending from the carriage frame 64 is asturdy hopper-shaped support structure 66 which has rigidly fixed to itslower end a carrying member 68 for a manipulator boom 70.

This boom 70 comprises generally a stationary piston member 72 and acooperating cylinder member 74, the latter being mounted forreciprocating longitudinal slide movement in a suitable slide journalformed in the carrying member 68 at the lower end of the supportingstructure 66. Fixed to and extending rearwardly from the carrying member68 are a pair of channel pieces 78 which are joined at their ends by afront cross piece 80, to which is fixed the tail end of a tubular pistonrod 82. It is from this cross piece 80 that the piston drives thecylinder boom 74. Fixed to the head end of this rod 82 is the pistonhead 84 of the piston member 72, this piston head 84 being locatedwithin the cylinder 74.

To supply a drive fluid (either compressed air or a hydraulic fluid) tothe boom 70, there is located concentrically within the rod 82 a feedline 86 leading through the piston head 84 so as to communicate with thehead chamber 88 defined by the cylinder 74 and the piston head 84. Theannular passage 90 defined by the piston rod 82 and the outer surface offeed line 86 communicates with the tail chamber 92 (also defined by thecylinder 74 and piston head 84, but also containing the rod 82) at alocation adjacent the piston head 84. This .annular pashead, generallydesignated 100, by which the boom 70 grips each of the forming plugs 22.The housing 102 for this gripper head 100 is fixed to the front end ofthe cylinder member 74 and is provided with a plurality of radiallydisposed longitudinal slots 104, each of which accommodates therein arelated gripping finger 106, likewise disposed longitudinally andarranged in a regular pattern about the circumference of the housing102. Each of the fingers 106 is pivotally mounted at 107 in its relatedslot 104 about an axis transverse to the longitudinal axis of thecylinder member 74 and generally tangential to the circumference of thehousing 102.

To cause the tips 108 of the fingers 106 to converge in .a grippingmovement toward the center axis of the cylinder member 74 there isprovided a cam plug 110 disposed within the housing 102 to engage thebase end 112 of the fingers 106. Extending rearwardly from the cam plug110 is a drive screw 114 which is moved longitudinally in the housing102 by means of a drive nut 116 which is turned by an electric or fluidoperated reversible motor 118 located in the housing 102. Rearwardmotion of the cam plug 110 causes the fingers 106 to grip the plug nosepiece 40, while forward motion of the plug 110 permits a spring 120 topush a positioning block 121 to spread the finger 106 and release theplug nose piece 36. At the rear of the housing 102 is a transversebulkhead 1 22 which isolates the jaw mechanism 100 from the head chamber88 in the cylinder member 74. To

' drive the motor 120, suitable feed lines 124 (either electric orhydraulic) are provided in the wall of the cylinder member 74 and reachoutwardly from the rear end thereof to connect to a suitable source ofdrive fluid.

frame 64 and driven from a stationary piston head 128 at the mid-lengthof the bridge 52. Extending longitudinally of the bridge 52 and reachingin opposite direction from the piston head 1% are a pair of piston rods130 and 132, each of which joins to a related end piece 60 of therectangular bridge frame 52. The piston head 128 partitions the interiorof the cylinder 126 into two chambers 134 and 136, each of whichcommunicates through the piston 128 with a related fluid supply passageformed in the interior of, respectively, piston rods 130 and 132. Thusby supplying fluid to either of the rods 130 or 132 the carriage 54 canbe driven in either direction along the length of the bridge 52.

-As will be described more fully hereinafter (and as shown in FIGURE 9),the carriage 54 has three operating positions, namely: a full rightposition at whichthe boom 70 is either placing a plug 22 on the mandrel32 or withdrawing it therefrom, a full left position where the plugcooling magazine (to be described hereinafter) is either taking a hotplug 22 from the boom 70 or supplying a cool plug 22 thereto, and anintermediate position at which the boom is stationed while the piercedshell 14 is being fed onto the forming plug 22 and onto the mandrel 32,from which station the boom 70 will follow the tail end of the piercedshell 14 toward the plug 22 before the tail end of the shell 14 haspassed over the plug 22.

To properly decelerate the carriage 54 as it travels to either of theextreme end positions on the bridge 52, the bridge 52 is provided with apair of cam switches 138 and 140 each of which is engaged by anactuating cam or by a related carriage wheel 58 respectively, mounted oncarriage frame 64. To stop the carriage 54 at its intermediate position,there is provided a pair of retractable stops 146 pivotally mounted on asuitable cross beam 148 reaching between the I beams 56. The two stops146 are caused to pivot into the path of the carriage frame 64 byextending a hydraulic or air actuated jack 150 con- 64 when the jack 150is fully extended. The carriage frame 64 is provided with a pair ofshock absorbers 154 to engage each of the stops 146. With the carriage54 so halted .by the stops 146, the drive fluid that enters the carriageactuating cylinder 126 is merely bypassed through a suitable reliefvalve in the hydraulic system. Retraction of the jack 150 causes thestops 146 to swing up and out of the path of the carriage frame 64.

To indicate generally the sequence in which the carriage 54 moves tothese three operating positions, assuming that the carriage has beenhalted by the stops 146 at its intermediate position (i.e. moderately tothe left, as seen in FIGURE 9, of the feed path of the billet 14) andthat the billet or shell 14 has reached the operating position indicatedin FIGURE 3 (i.e. beginning to be drawn inwardly by the work rolls 24and 26 and the ram 18 withdrawing from the billet 14), the operatingsequence is initiated by the rear end of the billet 14 pass ing by aninfrared detector 156 which is mounted from the floor or otherstationary object in the desired position. When the ram 18 has retractedsufliciently and the shell 14 has moved a sufficient distance forard(the detector 156 ascertaining this by sensing the abrupt reduction inintensity of heat rays transmitted thereto), fluid is caused to flowthrough line 130 into the chamber 134 of the cylinder 126 so that thecarriage 54 moves quickly toward its full right position (i.e. with theboom aligned with the feed path of the shell 14). Also fluid flowsrapidly into the head chamber 88 0f the boom cylinder 74 so that thehead 100 of the cylinder member 74 overtakes the rear end of the shell14 and actually reaches into the rear end of shell 14 to center on theprotruding nose piece 36 of the plug 22 on the mandrel 32 before therear end of the shell 14 has cleared the forming plug 22. The purpose ofthis is to enable the head 100 to engage the plug nose piece 36 whilethe pierced shell 14 is yet engaging the plug 22 so as to properlycenter the same.

When the shell 14 has moved forwardly to the extent that it clears theplug 22 on the mandrel 32 (as in FIG- URE 4), the boom 70, by means ofits gripping head 100, engages the nose piece 36 of plug 22 andwithdraws the plug from the mandrel 32. The carriage 70 moves to itsfull left position (the stop 146 having been retracted by the jack 150),and the cylinder member 74 of boom 70 moves rearwardly to its fullyretracted position. By the time the carriage 54 approaches its full leftposition, the cylinder 74 is fully retracted so that the plug 22 carriedin the gripper head 100 is deposited in the magazine of the plug cooler200 (to be described hereinafter). The carriage 54 and the boom 70remained at this full left position, While the plug cooler 200 removesthe hot plug 22 and places a cool plug 22 into the gripper head 100. Thegripper head 100 closes on this plug 22 and as the carriage 54 moves toits full right position,

the :boom 70 begins to extend, to transport this plug 22 to the mandrel28.

It is to be noted that when the plug manipulator 50 moves its head 100to grip the hot plug 22 on the mandrel 32, the plug is centered by thepierced shell 14, which is in turn located by the work rolls 24 and 26.However, when the plug manipulator 50 is carrying a cool plug 22 to themandrel 32, this mandrel 32 is unsupported along its length, and has atendency to sag. For this reason, there is provided mandrel positioner,generally designated 160, comprising a V-block 162 located beneath themandrel 28. This V-block 162 is hydraulically actuated by ,the mandrel28 and center the same.

a related jack 164 so as to be moved upwardly to engage When the plugmanipulator 50 has deposited the cool plug 22 on the front end of themandrel 28, and the carriage 54 begins to withdraw to its intermediatelocation, the V-block 162 drops away from the mandrel and another billet14 (or the same billet 14 making its second pass through the plugrolling mill) is moved by the ram 18 onto the cool plug 22 nowpositioned on mandrel 28.

' zine 204.

The plug cooler 200 provided by the present invention, I

comprises a water tank 202 in which is mounted for longitudinal movementalong, and rotary motion about, an axis paralleling the longitudinalaxis of the manipulator boom 70, a plug magazine 204.

Before describing in detail the structure and operation of this plugcooler 200, it should be indicated that each plug 22 comprises a body206 which provides the forming surface about which the shell 14 isshaped, and a plug mounting piece 208. (This is illustrated in FIG- UREll.) This piece 208 comprises a generally circular mounting flange 210which fits in a mating recess 210a in the rear of the plug 22, and apair of aligned dowel pins 212 and 214 which extend oppositely from thecenter of the flange 210 and are disposed perpendicular thereto. The onepin 212 extends through and beyond the plug body 206 and protrudestherebeyond to provide the aforementioned nose piece 36 by which theplug 22 is gripped by the manipulator gripping head 100, while the otherpin 214 fits in a mating socket in the free end of the mandrel 28, toprovide'a suitable mounting therefrom.

, Throughout the entire operation, the plug body 206 and the plugmounting piece 208 of each plug 22 remain together.

The aforementioned plug magazine 204 comprises two parallel,transversely disposed circular plates 216 and 218, longitudinally spacedand aligned with respect to one another and both fixedly secured to alongitudinal shaft 220, which in turn is journal mounted at the frontand rear of the tank 202 (as at 222 and 224, respectively) forlongitudinal and rotary motion. Evenly spaced about the peripheralportions of the plates 216 and 218 are a plurality of pairs (six herein)of matching slots 226 and 228, which open to the circumference of plates216 and 218, each slot 226 and 228 disposed to receive, respectively,dowel pins 214 and 212 of a related plug 22.

These .slots 226 and 228 are so angled with respect to the radial linesof plates 216 and 218 that when the magazine 204 is disposed with twopairs of slots 226 and 228 uppermoshthe pair of slots 226'and 228 whichare at the upper location nearest the manipulator boom 70 (this, asdescribed hereinafter, being the load and unload station) are disposedhorizontally and open toward the manipulator boom 70. Thus the boom 70can, simply by moving a plug 22 laterally, insert the plug into, orremove the plug 22 from, the magazine 204, with the dowel pins 214 and212 fitting into the related slots 226 and 228, with the plug body 206fitting partially between the magazine plates 216 and 218.

Located in the water tank 202 and positioned, respectively, in front ofand in back of the plug magazine 204, are a front and a rear spiderframe 230 and 232, each having a plurality of socket members 23'4- and 236, respectively, which correspond in number and location to the slots226 and 228 in the magazine 204, so as to interfit with, respectivelythe front and rear pins 214 and 212 of the plugs 22 and thus hold theseplugs 22 in the maga- To enable the plugs 22 to be loaded into andunloaded from the magazine 204 laterally, the rear spider 232 has nosocket member at the load and unload station. The .rear spider 232 isfixedly located in the tank 202, while the front spider 230 islongitudinally fixed, but is rotatably mounted by means of a collar 238about the shaft 220. It is this collar 238 which provides the slide androtary journal for the shaft 220, and this collar 238 is itself mountedfor rotary motion about the axis of the shaft 220 in a mounting post240.

Fixedly secured to the front end of the collar 238 is a radiallydisposed lever a-rm 242 by which an indexing jack 244 (i.e. a cylinderand a piston .ope-ratively disposed therein) rotates the collar 238 (andconsequently the front spider frame 230) in sixty degree increments. Tomove the shaft 220 longitudinally either toward the rear spider 232 orforwardly toward the front spider 230, there is provided alongitudinally disposed fluid actuated 8 7 jack 246 which engages therear end of the shaft 220 through a thrust bearing 248, this jack 246being mounted from a suitable support frame 250.

The front spider frame 230 is provided (see FIGURE 13) with an indexingplate 252 having a plurality of holes 254 arranged to interfit withcorresponding indexing pins 256 fixed on the back face of the frontmagazine plate 218.

The water tank 202 is provided with a suitable cold water inlet 2'58,and an outlet 260. The latter is arranged so as to maintain the waterlevel in the tank moderately above the rotary axis of the shaft 220 butbelow the uppermost part of the plug magazine 204. Thus as the magazine204- rotates through increments of sixty degrees, four plugs 22 are atall times immersed in the cold water bath of the water tank 202.

To describe the operation of this plug cooler 200, it will be assumedthat the manipulator boom 70 has withdrawn a hot plug 22 from themandrel 32 and is carrying the same toward the plug cooler 200, thelongitudinal jack 246 has pushed the magazine 204 to its furthestrearward position, so that each of the plugs 22 contained in themagazine 204 is free of the front indexed spider 230 but engages eachwith its one dowel pin 212 a related socket 236 of the rear spider 232,so that each of the plugs 22 is held in a related pair of magazine slots226 and 228.

The slots 226 and 228 at the upper portion of the magazine 204 nearestthe manipulating boom 70 (i.e. at the load and unload station) areempty, while each other pair of slots 226 and 228 carries a plug 22.When the manipulating boom 70 reaches the plug cooler, it is fullyretracted, and the hot plug 22 carried in the gripper head is slippedinto the magazine slots 226 and 228 at the load and unload station. Thegripper head 100' of the boom 70 releases, and the longitudinal jack 246is actuated so as to pull the magazine 204 forwardly. As the magazine204 so moves forwardly, the dowel pins 214 of each of the plugs 22 inthe magazine engage a related socket member 234 in the front spider 230,as the rear dowel pins 212 disengage their related socket members 236 inthe rear spider 232. Thus throughout this forward movement of themagazine 204, each of the plugs 22 and the magazine 204 are continuouslyengaged by either a front or rear socket member 234 or 236, so that theplugs 22 are held in their proper locations in the magazine 204.

When the magazine 204 is fully retracted, the indexing pins 256 haveengaged the indexing holes 254 in the indexing plates 252. Then theindexing jack 244 rotates the collar 238 and consequently the plate 252,and the magazine 204 through a 60 degree increment of travel.

Immediately after this, the longitdinal jack 246 moves the magazine 204rearwardly in the tank, so that a cool plug 22 which has now been liftedfrom the water bath to the load and unload station is pushed forwardwith the dowel pin 212 of this plug 22 being inserted into the gripperhead 100 of the manipulating boom 70. The jaw mechanism 100 then closeson the dowel pin 212 of this cool plug 22, and as the carriage 54 moveslaterally, this plug 22 moves from its load and unload station carriedby the boom 70.

It is to be understood that each of the aforedescribed moves of themanipulator 50 and the plug cooler 200 may be initiated by an operatormanually moving appropriate controls, or automatically by each movementof the apparatus engaging a switch to open a valve to initiate thesubsequent operating movement. Also, the operation may be accomplishedpart manually and part automatically, with the operator initiatingvarious portions of the operating sequence. Since such arrange ments ofcontrol apparatus are well known in the prior art, no attempt has beenmade to illustrate or describe the same.

It should be understood that the foregoing is merely illustrative ofcertain embodiments of the invention and many variationsmay be made bythose skilled in the art without departing from the spirit and scope ofthe invention.

Now therefore, I claim:

1. In a plug rolling mill, where a billet is fed along a longitudinalfeed path over a replaceable plug mounted at a working location on therear end of a longitudinally aligned mandrel, an apparatus to replace ahot plug on the mandrel with a cool plug and to provide for coolingplugs used in rotation in the plug rolling mill, said apparatuscomprising, in combination:

(a) a plug manipulator comprising a boom having a plug gripper attachedto one end thereof, said boom being mounted from a carying frame in amanner to be movable longitudinally with respect to said frame, andtransversely between said working location and a plug transfer stationwhich is spaced transversely from said feed path, and comprising powermeans to so move said gripper between said working location and saidplug transfer station,

(b) a plug cooler located at said plug transfer station comprising aplug carrier having a plurality of plug holding means, each arranged toreceive a related plug from and to deliver said related plug to saidmanipulator, said carrier being movable along a predetermined course inwhich each of said plug holding means in sequence moves its related plugfrom said transfer stat-ion, through a cooling zone and back to saidtransfer station.

2. The apparatus as recited in claim 1, wherein there is a mandrelpositioner for supporting the mandrel comprising locating means movabletransversely to engage said mandrel and hold said mandrel in alignmentwith said longitudinal feed path.

3. The apparatus as recited in claim 2, wherein said mandrel positionercomprises block means having a recess to receive said mandrel and meansto move said block generally vertically to lift said mandrel into aposition in alignment with said feed path.

4. The apparatus as recited in claim 1, wherein the boom is mounted formovement along a direction aligned with said feed path, so that saidgripper is able to reach into the rear end of said billet and grasp saidplug in its working position before the billet has cleared the plug.

5. The apparatus as recited in claim 1, wherein said manipulatorcomprises:

(a) a carrying frame providing horizontally and transversely alignedrail means,

(b) a carriage mounted on said rail means for horizontal transversemovement therealong,

(c) a manipulator boom mounted on said carriage for longitudinalmovement toward and away from said plug in its working position,

(d) said plug gripper being mounted on the front end of said boom.

6. The apparatus as recited in claim 1, wherein each of said plugholding means comprises slot means in said plug carrier, each of saidslot means being so arranged as to open transversely toward saidmanipulator gripping means so as to be able to receive its related plugby said manipulator moving said related plug transversely into said slotmeans at said transfer station.

7. The apparatus as recited in claim 6, wherein said plug carrier ismovable longitudinally to and away from said transfer station, so that ahot plug can be taken from said manipulator and a cold plug deliveredthereto by longitudinal movement of said plug carrier.

8. The apparatus as recite-d in claim 7, wherein said plug coolercomprises front and rear plate means, each of which has a plurality ofperipherally located slots, each slot matching a related slot of theother plate means so that there are a plurality of pairs of a front anda rear slot to receive respectively a front and rear pin of a relatedplug, said plug cooler having a front and a rear locating frame, eachframe provided with socket means for receiving said pins, said frontframe being located in front of said front plate means and said rearframe being located behind said rear plate means, and said plate meansbeing movable between a front position proximate said front frame and arear position proximate said rear frame, whereby at least one or theother of said frames is performing a pin engaging function so that saidplugs are each held in its related pair of slots.

9. The apparatus as recited in claim 8, wherein said front frame isrotatably mounted about its longitudinal axis and there are means to somove said front frame in predetermined increments about its longitudinalaxis so that each of said plugs can be moved from its transfer posit-ionthrough said cooling zone and back to said transfer station.

10. The apparatus recited in claim 1, wherein said plug coolercomprises:

(a) a cooling means defining a cooling zone and providing a coolingmedium in said cooling zone,

(b) a magazine comprising a pair of longitudinally spaced and alignedplate means, the general plane of each plate means being transverselydisposed, said plate means being secured to one another and rotatableabout a longitudinal axis,

(c) each of said plate means being provided with a plurality ofoutwardly disposed peripheral slots, each of which matches with arelated slot of the other plate means, so that there are matching pairsof longitudinally aligned front and rear slots, the front slot of eachpair being arranged to receive a related front pin of a related plugwith the rear slot in a similar manner being disposed to receive a rearpin of said related plug,

(d) a front and a rear plug pin receiving frame, the front frame beinglocated in front of the front plate means and the rear frame beinglocated behind rear plate means, each of said frames having a pluralityof evenly spaced sockets to receive a related plug pin to hold saidplugs in said magazine,

(e) means to move said magazine longitudinally be tween said front andrear frame, at least one of said frames holding said plugs at all timesas the magazine moves longitudinally, and

(f) means to rotate said magazine in predetermined increments so thateach pair of slots, carrying a related plug, moves in sequence to saidtransfer station.

11. The apparatus as recited in claim 10, wherein said plug coolingmeans comprises a fluid containing tank and said magazine is so disposedwith respect to said tank as to be partially submerged in the fluidcontained in said tank.

12. The apparatus as recited in claim 10, wherein said means to rotatesaid magazine comprises power means operatively connected to said frontplug pin holding frame, so that said magazine is rotated only in aforward position when operatively engaging said front frame.

13. In a plug rolling mill, where a billet is fed along a longitudinalfeed path over a replaceable plug mounted at a working location on therear end of a longitudinally aligned mandrel, an apparatus to replace ahot plug on the mandrel with a cool plug and to provide for coolingplugs used in rotation in the plug rolling mill, said apparatuscomprising, in combination:

(A) a plug manipulator comprising:

(a) a carrying frame providing horizontally and transversely alignedrail means,

(b) a carriage mounted on said r-ail means for horizontal transversemovement therealong, (c) a manipulator boom comprising a cylindermounted for longitudinal slide movement with respect to said carriage,and a piston operatively disposed within said cylinder and secured tosaid carriage so as to enable said cylinder to move longitudinally,

(d) a plug gripper mounted on the front end of said cylinder,

(B) a mandrel positioner comprising locating means movable transverselyto engage said mandrel and hold said mandrel in alignment with saidlongitudinal feed path,

(C) a plug cooler comprising:

(a) a cooling tank to contain a cooling fluid at a predetermined level,

(b) a magazine comprising a pair of longitudinally spaced and alignedplate means, the general plane of each plate means being transverselydisposed, said plate means being secured to one another and rotatableabout a longitudinal axis,

(c) each of said plate means being provided with a plurality ofoutwardly disposed peripheral slots, each of which matches with arelated slot of the other plate means, so that there are matching pairsof longitudinally aligned front and rear slots, the front slot of eachpair being arranged to receive a related front pin of a related plugwith the rear slot in a similar manner being disposed to receive a rearpin of said related plug,

(d) a front and a rear plug pin receiving frame, the front frame beinglocated in front of the front plate means and the rear frame beinglocated behind rear plate means, each of said frames having a pluralityof evenly spaced sockets to receive a related plug pin to hold saidplugs in said magazine,

(e) means to move said magazine longitudinally between said front andrear frame, at least one of said frames holding said plugs at all timesas the magazine moves longitudinally, and

(f) means to rotate said magazine in predetermined increments so thateach pair of slots, carrying a related plug, moves in sequence to saidtransfer station.

References Cited by the Examiner UNITED STATES PATENTS 2,005,310 6/1935Bark et a1. 72-201 2,635,492 4/ 1953 Gettig 7234Z 2,771,800 11/ 6Kritscher 72209 CHARLES W. LANHAM, Primary Examiner.

H. D. HOINKES, Assistant Examiner.

1. IN A PLUG ROLLING MILL, WHERE A BILLET IS FED ALONG A LONGITUDINALFEED PATH OVER A REPLACEABLE PLUG MOUNTED AT A WORKING LOCATION ON THEREAR END OF A LONGITUDINALLY ALIGNED MANDREL, AN APPARATUS TO REPLACE AHOT PLUG ON THE MANDREL WITH A COOL PLUG AND TO PROVIDE FOR COOLINGPLUGS USED IN ROTATION IN THE PLUG ROLLING MILL, SAID APPARATUSCOMPRISING, IN COMBINATION: (A) A PLUG MANIPULATOR COMPRISING A BOOMHAVING A PLUG GRIPPER ATTACHED TO ONE END THEREOF, SAID BOOM BEINGMOUNTED FROM A CARRYING FRAME IN A MANNER TO TO MOVABLE LONGITUDINALLYWITH RESPECT TO SAID FRAME, AND TRANSVERSELY BETWEEN SAID WORKINGLOCATION AND A PLUG TRANSFER STATION WHICH IS SPACED TRANSVERELY FROMSAID FEED PATH, AND COMPRISING POWER MEANS TO SO MOVE SAID GRIPPERBETWEEN SAID WORKING LOCATION AND SAID PLUG TRANSFER STATION, (B) A PLUGCOOLER LOCATED AT SAID PLUG TRANSFER STATION COMPRISING A PLUG CARRIERHAVING A PLURALITY OF PLUG HOLDING MEANS, EACH ARRANGED TO RECEIVE ARELATED PLUG FROM AND TO DELIVER SAID RELATED TO SAID